A typical holography technology is, for example, a technology of causing reference light and signal light to interfere with each other and recording the interference light on a hologram recording medium. In other words, at the time of recording, a light and dark pattern of the interference light, i.e., an intensity and a phase thereof are recorded on a recording medium. At the time of reproduction of the signal light, the recording medium is irradiated with the reference light, and thus diffracted light occurs from the recording medium. An observer can see the diffracted light as a stereoimage.
Patent Document 1 discloses an apparatus that irradiates a detector such as an image sensor with reproduction light to obtain a digital image at the time of reproduction of the signal light (see, for example, paragraphs [0004] to [0007] of Patent Document 1).
Further, there is also a so-called digital holography technology of acquiring the above-mentioned interference light as a digital image by using a solid-state imaging device. In the digital holography technology, data of the intensity and phase of the interference light is handled as digital data of an interference fringe image, and image processing is also necessary at least at the time of reproduction. Consequently, the digital holography technology is disadvantageous in a huge amount of data and a huge amount of data processing.
For another means of obtaining a stereoimage, Patent Document 2 discloses a display system using a screen of mist or water droplets. The display system includes a generator of a screen of mist or water droplets, and a projector that projects 3D content onto the mist or water droplets generated by the generator (see, for example, paragraph [0019] of Patent Document 2).
Patent Document 1: Japanese Patent Application Laid-open No. 2013-178860
Patent Document 2: Japanese Patent Application Laid-open No. 2013-17161